Couldn't*
because if you could care less if defeats the purpose of saying it.
But I DO agree with you!
Regarding the watch, I don't know about you guys but my phone is always with me or very near. Why would I need my watch to confirm my phone is in fact ringing? It would be cooler to predict when my phone is about to ring! I'd buy that.
This explains the 'I could care less' thing rather well
http://www.youtube.com/watch?v=om7O0MFkmpw